Synthesis of tetrapod like PbS microcrystals by hydrothermal route and its optical characterization

Microcrystalline PbS tetrapod like structure has been successfully prepared by a hydrothermal route using Pb(CH3COO)2.3H2O and thiourea as reagents and acrylamide (AA) as a surfactant. X-ray diffraction (XRD) studies confirmed the highly crystalline cubic PbS phase formation. Scanning electron microscopic study revealed the tetrapod like structures with length 1.5 μm and breadth 400-500 nm. Detail morphology and structure have been investigated by transmission electron microscopic studies also. Selected area electron diffraction and HRTEM lattice image confirmed the single crystallinity and preferential growth direction of the as-obtained samples. UV-vis spectrophotometric study showed the direct band gap of the PbS tetrapod ∼4.9 eV. The photoluminescence measurements showed that the emission peaks were located at 440 nm for all the excitation wavelength of 275-325 nm and are explained due to radiative recombination from the surface states.